The invention relates to a mobile crane with a vehicle framework and at least one support device positioned on the vehicle framework, whereby the at least one support device comprises a sliding beam box and at least one sliding beam supported therein in a telescopable manner.
Mobile cranes, because of their very nature, usually have several vehicle axles by means of which the mobile crane can be moved down a road. Because of the current legislation, a maximum axle load of 12 T is thereby permitted for road travel. As a rule, driving permits for large devices with a total weight of up to 100 T are issued relatively easily and quickly. If the total weight exceeds the limit of 100 T, however, then the expense for requesting a driving permit becomes considerably higher or no permits may be issued, as the case may be.
In order to observe the legally specified maximum weight for road travel, it is thus known to transport individual components of the mobile crane separately and to unite these with the mobile crane only at the installation point. The German patent DE 10 2008 032 739 A1 proposes, for example, the dismounting of the crane support, in order to transport it to the destination separately. The implementation proposed, however, relates to a special construction of a foldable support device with a swivellable base chest and a sliding beam that can be telescoped out from this. The support device is attached laterally to the mobile crane, and can be dismounted completely from the crane for road transport.
Furthermore, cranes are known which, instead of the foldable support, have a support integrated into the vehicle framework. This consists of a sliding beam box and a sliding beam that can be slid out of the sliding beam box. The sliding out occurs, as a general rule, perpendicularly to the longitudinal axis of the vehicle framework. In the case of large cranes with high total weight, the sliding beam is removed for the transport of the mobile crane in open road traffic, in order to thereby be able to meet the standards of open road traffic in regard to the permissible axle load, but without dispensing with the necessary support device. The advantage for load-bearing capacity is achieved at the price of increased equipment expense for the use of the crane.
In such supports, the sliding beam conveys very large support forces into the sliding beam box by means of a force couple. For the telescoping movement of the sliding beam, this is movably supported in the sliding beam box by means of support points. The bearing clearances selected, however, have to be as small as possible, in order to avoid tilting during the telescoping process. The small bearing clearance and the specific weight of the support beam, however, make the threading of the sliding beam into the sliding beam box at the installation point more difficult.